How to get a smooth look like this?
Maybe try bendy bones? Select your armature and in the Properties panel &gt; Object Data &gt; Viewport Display, choose B-Bone. Then in Edit or Pose mode, select a bone and in in the Properties panel &gt; Bone &gt; Bendy Bones, increase the Segments amount:

Here is what it gives (compared to bones with one segment only), you can play with Ease In and Ease Out values:

You could also use more than 2 bones, some with one segment, others with several:

What you show is special though, as the outer sides are flat while the inner is round, so maybe a corrective shapekey for the inner curve and a driver to activate it?